The invention relates to a process for the manufacture of a tape-shaped object of any desired thickness, width and length, formed from stacked and partially glued together film strips, in which one side of each film strip is provided over its entire width with adhesive strips, and the adhesive strips of directly consecutive film strips are arranged to be offset, where the film strips are stacked into a film strip stack, pressed against one another in the direction of stacking and glued together to form the tape-shaped object. A suitable device to complete the process is also part of the invention.
Two processes for manufacture of a tape-shaped object from partially glued together film strips are in essence currently known. The first process relates to the manufacture of blocks of film sheets laid on top of one another and provided with adhesive strips, with subsequent gluing of the individual sheets to one another under the effect of pressure and heat, where the blocks manufactured in this way are sawn into slices, the cut width of which corresponds to the subsequent thickness of the tape-shaped object. Gluing the individual slices together produces a virtually endless object. This method of manufacture is for example disclosed in DE-A-2342076 and is currently used in practice.
The disadvantage of this previously known manufacture by way of production of a block, with blocks being subsequently sawn up into individual slices, lies principally in the fact that during commercial manufacture the blocks are so thick that the transmission of heat into the block in order to trigger the adhesive process requires long heating and compression times and in addition can lead to an uneven temperature distribution with corresponding reduction in the quality of the end product. The subsequent cutting of a block into slices using a band saw leads to a considerable degree of waste. Moreover, four individual processing stages are necessary in order to manufacture the tape-shaped object formed from partially glued together film strips, namely
1. Stacking the sheets provided with adhesive strips
2. Compressing the stacked sheets into a block
3. Sawing the block into individual slices and
4. Gluing the individual slices into the quasi endless object.
In addition, gluing the individual slices produces points in the object which have a negative effect on the characteristics of the object, and which may therefore in some circumstances even have to be removed.
The second type of manufacture is based on film strips provided with adhesive strips, which are stacked on top of one another and are compressed into an endless tape-shaped object in the direction of stacking and with the addition of heat. Such a process is known for example from DE-C-3820718, in which a film web is provided continuously with longitudinal adhesive strips. The individual film strips are cut across the direction of movement of the film web on the line, are stacked on top of one another to form a film strip stack, and are compressed under pressure in the direction of stacking and with the addition of heat into an endless tape-shaped object.
The main disadvantage of this process involves primarily the low production speed, which cannot be significantly increased even when two film webs are simultaneously brought together for cutting of the individual film strips for the purposes of commercial manufacture of an endless tape-shaped object. Despite the advantages over traditional block manufacture, as regards improved heat application for gluing the film strip stack and the considerably reduced sawing waste when cutting the individual film strips, it has not so far been possible to implement the processes based on this principle in practice.
The invention seeks to solve the problem of creating a process of the type described at the outset, by way of which a tape-shaped object of high quality formed form partially glued together film strips can be commercially manufactured on a production line. A further aim is the creation of a suitable device to effect the process.